Fig. 4

Acidic and osmotic stress resistance assays. WT S4074, ΔqseBC, ΔapfA, ΔapfB, ΔapfC and ΔapfD were treated with 0.02 M HCl (a) and 0.50 M KCl (b) or tryptic soy broth and incubated for 3 h at 37 °C. Then the bacterial survival rates were calculated. Data presented are the mean ± SD (N = 3). *P < 0.05